Congenital vesicovaginal fistula.

Congenital vesicovaginal fistula is a very rare entity, the etiology of which has not been clearly elucidated because pathologic features have not been mentioned in previous reports. The case of a 4-year-old girl having incontinence resulting from a congenital vesicovaginal fistula joining with the left ectopic ureter from the hypoplastic kidney is described. This is thought to be the first presentation of congenital vesicovaginal fistula joining with ectopic ureter. A microscopic examination revealed the fistula consisting of transitional cell epithelium, suggesting an abnormal fusion of the ureteral bud and caudal end of the müllerian duct with the urogenital sinus.